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Using the Animated Figure 10.22 , the isothermal transformation diagram for an alloy of eutectoid composition, specify the nature of the final microstructure (in terms of microconstituents present and approximate percentages of each) of a small specimen that has been subjected to the following temperature treatments. In each case assume that the specimen begins at 760C and that it has been held at this temperature long enough to have achieved a complete and homogeneous austenitic structure. (a) Rapidly cool to 400 degrees C, hold for 2s, then quench to room temperature. (b) Rapidly cool to 400 degrees C, hold for 200s, then quench to room temperature. 100% pearlite 100% bainite 100% martensite 100% tempered martensite 50% pearlite +50% martensite 50% bainite +50% martensite 50% pearlite +25% bainite +25% martensite